I added a bunch of new songs and at first it said an odd format and couldn't play (even tho they were mp3s).. next it would just randomly delete the new stuff I added after an hour or 2

Now when I just tried go add a new folder of songs.. at first they sounded fine when the phone was still plugged to the computer, but when I unplugged and put on my earphones it was like jumbled polka instead of my songs

I have no clue what's wrong.. I rebooted both the computer and phone but that didn't help